JPH10168556A - Platinum-aluminized single crystal superalloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase resistance to deterioration of a single crystal superalloy contg. a large amt. of rhenium without sacrifying the mechanical properties thereof, prior to aluminizing treatment, by modifying the surface of a single crystal superalloy contg. a large amt. of rhenium to reduce the content of rheni um. SOLUTION: For example, on the surface of a single crystal superalloy contg. a large amt. of rhenium, a layer of Co as a suitable metal is formed by 2.5 to 12.5μ thickness by electroplating, which is subjected to heat treatment at 900 to 1150 deg.C for 1 to 4hr to diffuse Co into the superalloy, by which the content of rhenium in the surface of the superalloy is reduced. Or, heat treatment at 1100 deg.C for 3hr is executed to convert the surface into chromodizing. On the surface of the superalloy, a layer of platinum group metals formed, which is subjected to heat treatment to diffuse the platinum group metals into the superalloy, which is subjected to aluminizing at 700 to 1150 deg.C to form plasinum group metal aluminide coating. In this way, the life time and service life of the product can remarkably be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to the provision of aluminide coatings on superalloys, particularly single crystal superalloys.

[0002]

BACKGROUND OF THE INVENTION Single crystal superalloys have been developed for turbine blades and blades of gas turbine engines to provide the highest thermal strength to the turbine blades and blades. However, when the composition of the single crystal superalloy changes compared to the composition of the initial superalloy, the surface of these single crystal superalloys deteriorates. Further, turbine blades and turbine blades are required to have even longer service lives. Thus, these single crystal superalloy turbine blades and turbine blades are deteriorated by corrosion and oxidation, so that satisfactory results in terms of service life have not been obtained.

[0003] The above-mentioned single crystal superalloy will be briefly described.
, And relatively high levels of tungsten and tantalum to provide high thermal strength resistance.

[0004] These single crystal superalloys are very heat resistant due to rhenium, tungsten and tantalum.

In order to extend the service life and service life of a single crystal superalloy turbine blade and turbine blade, it is desirable to protect the surface of the single crystal superalloy turbine blade or turbine blade with a protective coating. A platinum aluminide coating is known as a protective coating commonly applied to turbine blades and turbine blades. The platinum aluminide coating is formed by first coating a turbine blade or turbine blade with platinum and then aluminizing the platinum-coated turbine blade or turbine blade using an aluminizing process. Formed on a coated turbine blade or turbine blade platinum coating. The aluminizing process is performed by processes well known to those skilled in the art, for example, a pack aluminizing process, an out-of-pack (non-contact) vapor phase aluminizing process, chemical vapor deposition, or other processes.

[0006]

However, single crystal superalloy turbine blades or turbine blades having a high rhenium content are platinum aluminized using a conventional process, wherein the coating and the single crystal superalloy are used. At the interface with the alloy, a topologically densely packed phase is formed that is brittle on the structure of the alloy that weakens the mechanical strength. A single crystal superalloy with a high rhenium content contains 4 wt% rhenium.
The above is included. These topologically densely packed phases that weaken the mechanical structure that weaken the mechanical strength are formed by directly aluminizing as a structural treatment or by exposing to high temperatures.
Such topologically densely packed phases that are brittle in structure include higher levels of rhenium, tungsten, and chromium than single crystal superalloys, and the levels of rhenium in single crystal superalloys When it is increased, it is more easily formed. The topologically densely packed phase, which is brittle in the alloy structure, increases quantitatively by increasing the processing time at high temperatures. However, topologically densely packed phases that are brittle in alloy structure adversely affect the mechanical properties of single crystal superalloys. Therefore, the use of conventional platinum aluminide coatings to increase the resistance of a single crystal superalloy rich in rhenium to degradation must be made at the expense of the mechanical properties and strength of the single crystal superalloy. Absent.

[0007] Other protective coatings commonly applied to turbine blades and blades are aluminide-silicide coatings, platinum aluminide-silicide coatings, simple aluminide coatings, and other suitable aluminide coatings.

The aluminide coating is formed using an aluminizing process by an out-of-pack vapor phase aluminizing process, a packed aluminizing process, chemical vapor deposition, or other processes well known to those skilled in the art.

One method of forming an aluminide-silicide coating is to deposit a silicon-filled organic slurry on the surface of a superalloy and pack aluminize as described in US Pat. No. 4,310,574. Aluminum carries silicon from the slurry as aluminum diffuses into the superalloy. Another method of forming an aluminide-silicon compound coating involves depositing a slurry containing elemental aluminum and silicon metal powder on a superalloy surface and then heating to 760 ° C. or higher to melt the aluminum and silicon in the slurry. These react with the superalloy and diffuse into the superalloy. Another method of making an aluminide-silicide coating is disclosed in US Pat.
The repetitive application and heat treatment of the slurry containing aluminum and silicon as described in US Pat. Another method of making aluminide-silicide coatings is to coat a eutectic aluminum-silicon slurry or a slurry of elemental aluminum and silicon metal powder with a superalloy surface, as described in published European Patent Application 0619856A. The thickness of the surface layer is increased and the silicon content is reduced, and the layer of the superalloy is a layer composed of layers in which an aluminide phase and a silicide phase are alternately and continuously laminated. Form and make.

One method of making a platinum aluminide-silicide coating is disclosed in published International Patent Application No.
Coating the turbine blades or superalloys of the turbine blades with platinum, as described in US Pat.
Heating diffuses the platinum into the turbine blade and then diffuses the aluminum and silicon from the molten state simultaneously into the turbine blade enriched with platinum. Another method of making a platinum aluminide-silicide coating is disclosed in published European patent application no.
As described in 54542A, a superalloy turbine blade is coated with platinum and then heat treated to diffuse the platinum into the turbine blade to form a silicon layer and then aluminizing. Silicon can also be diffused into turbine blades having platinum, as described in European Patent Application No. 0654542A.
Another method of making a platinum aluminide-silicide coating is to electrophoretically deposit platinum-silicon powder on a turbine blade and heat treat the platinum and silicon into the turbine blade, as described in U.S. Pat. No. 5,057,196. Diffusion, electrophoretic deposition of aluminum and chromium powder, followed by heat treatment to diffuse aluminum and chromium into the turbine blades.

The above-mentioned international patent application WO95 / 23243A
Using the method described in paragraph 1 to convert a single crystal superalloy turbine blade or
It has been found that coating with an aluminide-silicide coating forms a topologically densely packed phase with a brittle alloy structure at the interface between the coating and the single crystal superalloy. Coating a rhenium-rich single crystal superalloy turbine blade or turbine blade with a platinum aluminide-silicide coating by other methods described above results in the formation of a topologically densely packed phase in which the alloy structure is brittle. Conceivable.

Using the method of US Pat. No. 5,547,770, coating a turbine blade or turbine blade of a single crystal superalloy rich in rhenium with a platinum aluminide-silicide coating, the coating and the single crystal superalloy are coated. It was also found that a topologically densely packed phase was formed at the interface between the alloy and the brittle alloy structure. It is believed that coating a turbine blade or turbine blade of a single crystal superalloy with a high rhenium content with a platinum aluminide-silicide coating by the other methods described above results in the formation of a fragile phase in the alloy structure.

The formation of topologically densely packed phases in which the alloy structure is fragile is due to the high rhenium content of the single crystal superalloys, and these phases are reduced during the simple aluminizing process. It is considered to be formed in

It can be further stated that as long as a platinum aluminide-silicide coating, an aluminide-silicide coating or a simple aluminide coating is used, a single crystal superalloy having a high rhenium content without sacrificing mechanical properties. The point is that resistance to deterioration of the single crystal superalloy cannot be increased. Therefore, the solution of this problem is the subject of the present invention.

[0015]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and the present invention provides a single-crystal superalloy having a high rhenium content to solve the above-mentioned problems. A method for aluminizing is provided.

The method for aluminizing a single crystal superalloy with a high rhenium content according to the present invention comprises the following steps: (a) modifying the surface of the single crystal superalloy with a high rhenium content; And (b) aluminizing the surface of the single crystal superalloy with a high rhenium content to form an aluminide coating.

The step (a) is a step of reducing rhenium content on the surface of a single crystal superalloy having a high rhenium content.

Alternatively, step (a) comprises depositing a suitable metal layer on the surface of a single crystal superalloy containing high content of rhenium and heat treating the appropriate metal at the high content. This is a step of diffusing into the single crystal superalloy containing rhenium and lowering the rhenium content on the surface of the single crystal superalloy containing high content rhenium.

The suitable metal described above may be any metal that modifies the diffusion characteristics and reduces the composition of the region with high rhenium content.
For example, metals that are compatible with single crystal superalloys, such as cobalt, chromium, and the like.

In the step (a), a single crystal superalloy containing rhenium in a high content by electroplating means, sputtering means, pack diffusion means, out-of-pack diffusion means, chemical vapor deposition means or physical vapor deposition means, etc. The above-mentioned appropriate metal is deposited on the substrate.

The invention has particular application to platinum-aluminide coatings, platinum-aluminide-silicide coatings and aluminide-silicide coatings, but is applicable to all single crystal superalloys with high rhenium content and all aluminide coatings in superalloys. Things.

In a conventional prior art single crystal superalloy platinum aluminizing process, the single crystal superalloy is electroplated with a platinum layer and the platinum plated single crystal superalloy is treated under reduced pressure. To diffuse the platinum of the platinum layer into the single crystal superalloy. The heat-treated platinum-plated single crystal superalloy is aluminized using conventionally known pack aluminizing, non-contact gas phase aluminizing, chemical vapor deposition, or other suitable means. Aluminized and diffused in this way,
The platinum-plated single crystal superalloy is then heat treated in a protective atmosphere to maximize the microstructure and composition of the platinum aluminide coating, and to provide the mechanical properties and mechanical strength of the single crystal superalloy described above. To the best.

[0023] During the heat treatment performed after depositing the platinum layer on the single crystal superalloy to diffuse the platinum of the platinum layer into the single crystal superalloy, the heat treatment between the platinum and the single crystal superalloy. Diffuses to form a surface layer containing platinum, nickel and other superalloy elements. The heat treatment diffusion step is performed with sufficient time and temperature so that the composition of the diffused platinum layer becomes appropriate, and the required platinum aluminide is passed through the subsequent aluminging process and heat treatment process. A coating is obtained. An enlarged cross section of a conventional platinum aluminide coating 12 applied to a single crystal superalloy substrate 10 is shown in FIG.

However, when a single crystal superalloy with a high rhenium content is heat treated after the platinum layer is deposited, the platinum diffuses inward, causing rhenium and other refractory elements such as tungsten and chromium to become enriched. A zoning zone is formed in front of the inwardly diffusing platinum. And in the subsequent aluminizing and heat treatment steps performed to produce the required platinum aluminide coating, a zone where the above-mentioned rhenium and other refractory elements, such as tungsten and chromium, are enriched is present in the coating. It is kept as it is. Such zones, which are enriched with such rhenium and other refractory elements, act as initiators, forming a topologically densely packed phase in which the alloy structure is fragile. The phase in which this alloy structure is densely packed in a weakly topological shape has a needle (acicular or acicular crystal) shape in cross section.

The above topologically densely packed phase forms at the interface between the rhenium-rich single crystal superalloy and the platinum aluminide coating. The topologically densely packed phase occurs after all of the steps of forming the platinum aluminide coating have been completed or after exposing the platinum aluminide coating and the rhenium-rich single crystal superalloy to high temperatures. Formed in any of the above. Such topologically densely packed phases contain higher levels of rhenium than single crystal superalloys and are more likely to form as the rhenium content of the single crystal superalloy increases. The areas of the topologically densely packed phase described above affect the performance of single crystal superalloy components because they have lower creep strength than single crystal superalloys. Thus, the effective load bearing cross section of the turbine blade or turbine blade is reduced.

A single crystal superalloy substrate 20 rich in rhenium
FIG. 3 shows an enlarged cross section of a conventional platinum aluminide coating 22 applied after aging at high temperature.
Shown in It is evident from FIG. 3 that an accompanying topologically densely packed phase 24 is present at the interface between the platinum aluminide coating 22 and the rhenium-rich single crystal superalloy substrate 20. is there.

According to the present invention, a platinum layer is diffused into a rhenium-rich single crystal superalloy, and in a subsequent heat treatment step, rhenium and other refractory elements are enriched before the diffused platinum layer. To modify the surface of the rhenium-rich single-crystal superalloy so that no zones are formed in the state of being exfoliated, whereby the subsequent rhenium-rich single-crystal superalloy is No such topologically densely packed phases are formed between the alloy and the platinum aluminide coating.

[0028]

Next, preferred embodiments of the present invention will be described. Example 1 Conventional rhenium content is lower nickel-based single crystal superalloy, such as CMSX ₄ was platinum aluminised by the following means.

CMSX ₄ is located in Michigan, USA
Manufactured by Canon-Maskegon Corporation, located at 2875 Lincoln Street, Muskegon, 49443-9506, whose nominal composition is tungsten
6.4% by weight, 9.5% by weight of cobalt, chromium
5% by weight, Rhenium 3.0% by weight, Aluminum
5.6% by weight, tantalum 6.5% by weight, titanium 1.
0% by weight, 0.1% by weight of hafnium, molybdenum
0.6% by weight, the balance being nickel.

Electroplating, sputtering, CVD, P
2.5 micron to 1 micron for nickel-based single crystal superalloys with low rhenium content by VD or other suitable method
A platinum layer having a thickness in the range of 2.5 microns is deposited and applied under reduced pressure or in a protective atmosphere for a period of 1 to 4 hours.
Heat treatment at a temperature in the range of 00 ° C. to 1150 ° C. diffused the platinum into the nickel-based single crystal superalloy with low rhenium content. More specifically, the platinum layer was deposited by electroplating to a thickness of 7 microns and the heat treatment was performed under reduced pressure for 1 hour at a temperature of 1100 ° C.

A nickel-based single crystal superalloy with a low rhenium content on which a platinum layer has been deposited and in which the platinum has been diffused is then packed aluminized, out-of-pack aluminizing (non-contact aluminizing). Or 700 ℃ by CVD aluminizing means
Aluminizing was performed in a temperature range of 〜1150 ° C. More specifically, a low rhenium content nickel-based single crystal superalloy to which a platinum layer was deposited and into which the platinum had been diffused was packed aluminized at 875 ° C. for 20 hours.

The nickel-based single crystal superalloy with a low rhenium content, with the platinum layer aluminized, was then treated at 1100 ° C. for 1 hour and 870 ° C. for 16 hours under reduced pressure or in a protective atmosphere.

A low rhenium content nickel-based single crystal superalloy with a platinum aluminide coating as shown in FIG. 1 was made. Samples of a platinum-aluminide-coated low rhenium nickel-based single crystal superalloy were subjected to periodic oxidation tests at 1050 ° C, 200 hours and 1100 ° C, 100 hours. Even below the platinum aluminide coating, there was no topologically densely packed phase of needle-like layers that weakened mechanical strength.

EXAMPLE 2 Some samples of nickel-based single crystal superalloys with a high rhenium content, such as CMSX10, were platinum aluminized by the following means. The nickel-based single crystal superalloy with high rhenium content can be obtained by CMS
Known as X10, Michigan, USA 49
Manufactured by Canon-Maskegon Corporation, 2875 Lincoln Street, Muskegon, 443-9506. The nominal composition of this alloy is as follows: tungsten 3.5-6.5% by weight, cobalt 2.0-5.0% by weight, chromium 1.8-3.0% by weight, rhenium 5.0.
5 to 6.5 wt%, aluminum 5.3 to 6.5 wt%, tantalum 8.0 to 10.0 wt%, titanium 0.2 to
0.8% by weight, molybdenum 0.25 to 0.15% by weight,
Niobium 0-0.03% by weight, hafnium 0.02
-0.05% by weight, carbon 0-0.04% by weight, the balance being nickel.

Electroplating, sputtering, CVD, P
2.5 micron to 1 micron for nickel based single crystal superalloys with high rhenium content by VD or other suitable method
A platinum layer having a thickness in the range of 2.5 microns is deposited and applied under reduced pressure or in a protective atmosphere for a period of 1 to 4 hours.
Heat treatment at a temperature in the range of 00 ° C. to 1150 ° C. diffused the platinum into the nickel-based single crystal superalloy with a high rhenium content. More specifically, the platinum layer was deposited by electroplating to a thickness of 7 microns and the heat treatment was performed under reduced pressure for 1 hour at a temperature of 1100 ° C.

[0036] A nickel-based single crystal superalloy with a high rhenium content with a platinum layer deposited and the platinum diffused is then packed aluminized, out-of-pack aluminizing (non-contact aluminizing). Or 700 ℃ by CVD aluminizing means
Aluminizing was performed in a temperature range of 〜1150 ° C. More specifically, a platinum-deposited, rhodium-rich nickel-based single crystal superalloy into which the platinum had been diffused was packed aluminized at 1080 ° C. for 6 hours.

The nickel-based single crystal superalloy sample with a high rhenium content in which the platinum layer was aluminized was then heated at 1100 ° C. for 1 hour in a protective atmosphere.
Treated at 870 ° C. for 6 hours.

The high rhenium content nickel-based single crystal superalloy coated with the platinum aluminide coating 22 has a cross-sectional structure as shown in FIG. Examination of one of the above samples revealed a zone of poor mechanical strength reaching a depth of 30 microns at the interface between the platinum aluminide layer and the high rhenium content nickel-based single crystal superalloy. The zone contained topologically densely packed phases.

Periodic oxidation tests of multiple samples of a nickel-based single crystal superalloy with a high rhenium content coated with a platinum aluminide coating at 1100 ° C. for 100 hours showed that the platinum aluminide layer and the rhenium At the interface between the high content nickel-based single crystal superalloy, a topologically densely packed phase is created that weakens the mechanical strength of the needle-shaped layer in cross-section and is 160 microns deep It has been found that a continuous zone up to.

A nickel-based single crystal superalloy substrate 20 with a high rhenium content provided with a platinum aluminide coating 22 after aging at a temperature of 1100 ° C.
The topologically densely packed phase 24 having the cross-sectional structure shown in FIG.
Was obtained.

Example 3 Some samples of nickel-based single crystal superalloys with a high rhenium content were platinum aluminized by the following means. The rhenium-rich nickel-based single crystal superalloy is known as CMSX10,
Manufactured by Canon-Muskegon Corporation, 2875 Lincoln Street, Muskegon, 49443-9506, Michigan, USA. The nominal composition of this alloy is as described above.

The surface of the sample of the nickel-based single crystal superalloy with a high rhenium content is coated with chromium by electroplating, sputtering, CVD, PVD or any other suitable method and thermal diffusion treatment under reduced pressure or in a protective atmosphere. Modified to be an enriched surface layer. More specifically, this chromium-rich treatment is performed out-of-pack chromium treatment (non-contact chromium treatment) under the conditions of 3 hours and 1100 ° C.
To form a chromium-enriched surface layer reaching a depth of 15 microns.

Electroplating, sputtering, CVD, P
Depositing a chromium-enriched, rhenium-rich, nickel-based single crystal superalloy by VD or other suitable method with a platinum layer having a thickness in the range of 2.5 microns to 12.5 microns. Heat treated at a temperature in the range of 900 ° C. to 1150 ° C. for 1 to 4 hours under reduced pressure or in a protective atmosphere to diffuse the platinum into the nickel-based single crystal superalloy with a high rhenium content . More specifically, the platinum layer was deposited by electroplating to a thickness of 7 microns and the heat treatment was performed under reduced pressure for 1 hour at a temperature of 1100 ° C.

The chromized, platinum layer deposited, the platinum diffused nickel-based single crystal superalloy with a high rhenium content is then packed aluminized, out-of-pack aluminizing (non-aluminum). Contact aluminizing) or aluminizing was performed in a temperature range of 700 ° C. to 1150 ° C. by means of CVD aluminizing. More specifically, a sample of a chromized, platinum-deposited, platinum-diffused, high-rhenium-containing, nickel-based single crystal superalloy comprises:
Time aluminized at 1080 ° C. by out-of-pack aluminizing means.

The chromated, rhenium-rich, nickel-based single crystal superalloy with the aluminized platinum layer was then treated at 1100 ° C. for 1 hour and 870 ° C. for 16 hours in a protective atmosphere.

Examination of one of the above samples revealed that the interface between the platinum aluminide layer and the high rhenium content nickel-based single crystal superalloy was topologically densely packed with poor mechanical strength. No zones containing phases were found.

Some of the samples were heated at 1100 ° C., 1
Inspection after exposure to an oxidizing environment under conditions of 00 hours also revealed that the interface between the platinum aluminide layer and the high rhenium content nickel-based single crystal superalloy was a needle-shaped layer at the interface. No generation of topologically densely packed phases weakening the strength was seen.

The high rhenium content nickel-based single crystal superalloy 30 with the chromium modified platinum aluminide coating 32 has a cross-sectional structure as shown in FIG.

EXAMPLE 4 Samples of high rhenium content nickel-based single crystal superalloys were platinum aluminized by the following means. The rhenium-rich nickel-based single crystal superalloy is known as CMSX10,
Manufactured by Canon-Muskegon Corporation, 2875 Lincoln Street, Muskegon, 49443-9506, Michigan, USA. The nominal composition of this alloy is as described above.

The surface of the sample of the nickel-based single crystal superalloy with a high rhenium content is coated with cobalt by electroplating, sputtering, CVD, PVD or any other suitable method and thermal diffusion treatment under reduced pressure or in a protective atmosphere. Modified to be an enriched surface layer. Cobalt layer, electroplating, sputtering, C
A nickel-based single crystal superalloy with a thickness of 2.5 microns to 12.5 microns and a high rhenium content is deposited by VD, PVD or other suitable method for a time of 1 hour.
The heat treatment was performed for 4 hours at a temperature of 900 ° C. to 1150 ° C. under reduced pressure or in a protective atmosphere.

More specifically, the cobalt layer is deposited by electroplating on a 7 micron thick nickel-rich single crystal superalloy with a high rhenium content for 1 hour at a temperature of 1100 ° C. Heat treated under reduced pressure.

Electroplating, sputtering, CVD, P
A cobalt layer enriched rhenium-rich nickel-based single crystal superalloy is deposited by VD or other suitable method with a platinum layer having a thickness in the range of 2.5 microns to 12.5 microns. The platinum was diffused into the nickel-based single crystal superalloy with a high rhenium content by heat treatment under reduced pressure or in a protective atmosphere for 1 to 4 hours at a temperature ranging from 900C to 1150C. More specifically, the platinum layer was deposited by electroplating to a thickness of 7 microns and the heat treatment was performed under reduced pressure for 1 hour at a temperature of 1100 ° C.

A nickel-enriched nickel-based superalloy with a high rhenium content, which is enriched with cobalt and has a platinum layer deposited thereon, is then packed.
Aluminizing was performed by aluminizing, out-of-pack aluminizing (non-contact aluminizing) or CVD aluminizing in a temperature range of 700 ° C to 1150 ° C. More specifically, a cobalt-enriched, platinum layer deposited, platinum-diffused nickel-based single crystal superalloy sample with a high rhenium content was taken out of pack at 1080 ° C. for 6 hours. -Aluminized by aluminizing means.

The cobalt-enriched nickel-based single crystal superalloy with the platinum layer aluminized and enriched with rhenium was then treated at 1100 ° C. for 1 hour and 870 ° C. for 16 hours in a protective atmosphere.

Examination of one of the above samples showed that the interface between the platinum aluminide layer and the high rhenium content nickel-based single crystal superalloy was topologically densely packed with poor mechanical strength. No zones containing phases were found.

Platinum modified with cobalt
An enlarged cross-sectional structure of a nickel-based single crystal superalloy substrate 40 having a high rhenium content and having an aluminide coating 42 is shown in FIG.

Some of the samples were heated at 1100 ° C., 1
Inspection after exposure to an oxidizing environment under conditions of 00 hours also revealed that the interface between the platinum aluminide layer and the high rhenium content nickel-based single crystal superalloy was a needle-shaped layer at the interface. No generation of topologically densely packed phases weakening the strength was seen.

FIG. 6 shows an enlarged cross-sectional structure of a high rhenium content nickel-based single crystal superalloy substrate 40 having a platinum modified aluminide coating 42 after exposure to an oxidizing environment.

Prior to depositing platinum on the high rhenium content nickel-based single crystal superalloy, the level of rhenium on the surface or surface layer of the high rhenium content nickel-based single crystal superalloy is reduced. It is also possible to prepare surfaces of nickel-based single crystal superalloys with a high rhenium content. This can be achieved by using a gas, which selectively reacts with rhenium in the superalloy at high temperature and removes it,
Rhenium can be removed from the surface of nickel-based single crystal superalloys with a high rhenium content.

Although the invention applies to nickel-based single crystal superalloys with a high rhenium content, the invention also applies to any nickel-based superalloy with a high rhenium content.

The present invention also provides for the application of a platinum group metal aluminide coating to a nickel based superalloy having a high rhenium content for a ceramic refractory coating such as, for example, a ceramic refractory coating by plasma spraying or PVD. Applied.

Although the invention has been described with reference to a platinum aluminide coating, the invention also applies to platinum aluminide-silicide coatings, aluminide-silicide coatings and simple aluminide coatings or other suitable aluminide coatings.

In the case of a platinum aluminide-silicide coating, the surface of a single crystal superalloy having a high rhenium content may be provided with a suitable metal such as, for example, chromium or cobalt and heat treated or treated with a platinum aluminide. -Reduce or modify rhenium content before silicide film formation.

In the case of aluminide-silicide and aluminide coatings, the surface of the single crystal superalloy with a high rhenium content may be provided with a suitable metal such as, for example, chromium or cobalt and heat treated or aluminide coating. Alternatively, the rhenium content is lowered or modified before the formation of the aluminide-silicide film.

The more detailed description of the coatings described above is as already described, and for a more detailed description, reference can be made to said patents and published applications.

[0066]

As described above, according to the present invention, the resistance to deterioration is increased without sacrificing the mechanical strength characteristics of the single crystal superalloy, and the gas produced by the single crystal superalloy is increased. The life time and product life of a product based on a single crystal superalloy such as a turbine blade and a turbine blade of a turbine engine can be drastically extended.

[Brief description of the drawings]

FIG. 1 is a photomicrograph showing an enlarged cross-sectional view of a prior art platinum aluminide coating applied to a single crystal superalloy having a low rhenium content.

FIG. 2 is a photomicrograph showing an enlarged cross-sectional view of a prior art platinum aluminide coating applied to a single crystal superalloy having a high rhenium content.

FIG. 3 is a micrograph showing an enlarged cross-sectional view of a prior art platinum aluminide coating applied to a high rhenium content single crystal superalloy after aging at elevated temperatures.

FIG. 4 shows a chromium modified platinum alloy according to the invention applied to a single crystal superalloy with a high rhenium content.
It is a microscope picture which shows the expanded sectional view of an aluminide coating.

FIG. 5 is a micrograph showing an enlarged cross-sectional view of a cobalt-modified platinum aluminide coating according to the present invention applied to a single crystal superalloy having a high rhenium content.

FIG. 6 is a photomicrograph showing an enlarged cross-sectional view of a cobalt-modified platinum aluminide coating according to the present invention applied to a high rhenium content single crystal superalloy after aging at elevated temperatures.

[Explanation of symbols]

10, 20, 30, 40 Single crystal superalloy substrate 12, 22 Platinum aluminide coating 32 Platinum aluminide coating modified with chromium 42 Platinum aluminide coating modified with cobalt

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C23C 10/58 C23C 10/58 14/14 14/14 B 16/06 16/06 (71) Applicant 595181151 Chromalloy United Kingdom Limited Chromalloy United Kingdom Limited Nottingham Energy 163, UK Earlsey, Eastwood, Link Mel Road 11 Linkmel Road, Eastwood, Nottingham NG16 3RZ, England 72 England N. Nottingham Warrenton Parkside 6

Claims (28)

[Claims] 1. A method for aluminizing a rhenium-rich superalloy comprising the steps of: (a) modifying the surface of a rhenium-rich single crystal superalloy; and (b) rhenium content. Forming aluminide coating by aluminizing the surface of a single crystal superalloy, which is often used. 2. The method of claim 1, wherein step (a) comprises reducing rhenium content on the surface of the rhenium-rich superalloy. 3. The step (a) comprises depositing a layer of a suitable metal on the surface of a high-content rhenium-containing superalloy and heat-treating the high-content rhenium-containing superalloy. 2. The method as claimed in claim 1, comprising the step of lowering rhenium content at the surface of said high content rhenium-containing single crystal superalloy, diffusing into the superalloy. 4. The step (a) comprises the steps of: using a high content of rhenium by electroplating means, sputtering means, pack diffusion means, out-of-pack (non-contact) diffusion means, chemical vapor deposition means or physical vapor deposition means. 4. A method as claimed in claim 3 comprising depositing said suitable metal on a single crystal superalloy comprising the same. 5. The method according to claim 3, wherein the step (a) is performed on the surface of a superalloy containing rhenium at a high content of a metal having compatibility with a superalloy such as cobalt, chromium and the same metal. 4. The method claimed in 4. 6. The step (a) is performed at 900 ° C. to 1150 ° C.
6. A method as claimed in claim 3, comprising performing a heat treatment at a temperature in the range of 1 ° C. for a period of 1 hour to 4 hours. 7. The step (a) comprises applying a cobalt layer to the high content rhenium-containing superalloy to a thickness of 2.5 to 12.5 microns by electroplating means.
4. The method as claimed in claim 3, comprising performing a heat treatment at a temperature in the range of 00C to 1150C for a time of 1 hour to 4 hours. 8. The step (a) is performed at a temperature of 1100 ° C.
4. A method as claimed in claim 3 including chromizing the surface of said high content rhenium containing superalloy under conditions of time. 9. The step (b) is performed at 700 ° C. to 1150 ° C.
A method as claimed in any one of claims 1 to 8, comprising aluminizing in a temperature range of ° C. 10. The method of claim 1, wherein step (b) comprises pack aluminizing, out-of-pack (non-contact) vapor phase aluminizing, chemical vapor deposition or slurry aluminizing. Way done. 11. The method as claimed in claim 1, wherein the high-content rhenium-containing superalloy contains 3.5% to 8% by weight of rhenium. 12. The method as claimed in claim 11, wherein the high-content rhenium-containing superalloy is based on nickel. 13. The superalloy having a high content of rhenium comprises 3.5-6.5% by weight of tungsten and 2.2% by weight of cobalt.
0-5.0% by weight, 1.8-3.0% by weight of chromium, 5.5-6.5% by weight of rhenium, 5.3-6.0% of aluminum.
5 wt%, tantalum 8.0 to 10.0 wt%, titanium 0.2 to 0.8 wt%, molybdenum 0.25 to 0.15
Weight%, niobium 0 to 0.03 weight%, hafnium 0.02 to 0.05 weight%, carbon 0 to 0.04 weight%,
2. The method of claim 1, wherein the balance is nickel and associated impurities.
A method as claimed in claim 1 or claim 12. 14. The method according to claim 1, wherein the following step is added between the step (a) and the step (b): (c) the rhenium content is Depositing a layer of platinum group metal on the modified surface of the superalloy, and (d) heat treating the rhenium-rich superalloy having the layer of platinum group metal deposited thereon, thereby converting the platinum group metal to rhenium. The following steps are added after step (b), diffusing into the rich superalloy: (e) Aluminized, rhenium-rich superalloy with a layer of platinum group metal deposited Heat-treating to form a platinum group metal aluminide coating. 15. The method of claim 14, wherein step (c) includes forming a layer of platinum metal to a thickness of 2.5 microns to 12.5 microns by electroplating, sputtering CVD or PVD. Way. 16. The method as claimed in claim 14, wherein step (c) comprises forming a platinum layer. 17. The method according to claim 1, wherein the step (c) is performed at 900 ° C. to 115 ° C.
17. The method as claimed in claim 14, 15 or 16, comprising performing a heat treatment at a temperature in the range of 0 [deg.] C for a time of 1 hour to 4 hours. 18. The method according to claim 14, further comprising a step (f) of applying a ceramic heat-resistant coating to the platinum group metal aluminide coating. 19. The method as claimed in claim 18, wherein the step of applying the ceramic refractory coating is by plasma spraying or PVD. 20. The method according to claim 1, wherein the step (b) comprises, during the aluminizing step, diffusing silicon into a superalloy having a high rhenium content to form an aluminide-silicide coating. The billed method. 21. Depositing and heat treating a slurry containing elemental aluminum and silicon powder,
21. The method as claimed in claim 20, comprising the step of diffusing aluminum and silicon into a rhenium-rich superalloy. 22. A method as claimed in claim 21 including the step of repeatedly depositing a slurry containing elemental aluminum and silicon powder and heat treating to diffuse aluminum and silicon into the superalloy having a high rhenium content. Method. 23. The method of claim 14, including the step of diffusing silicon into a rhenium-rich superalloy during step (b) or during step (d). 24. A slurry containing elemental aluminum and silicon powder is deposited and heat treated,
24. The method as claimed in claim 23, including the step of diffusing aluminum and silicon into the rhenium-rich superalloy. 25. The method of claim 24, including the step of repeatedly depositing and heat treating a slurry containing elemental aluminum and silicon powder to diffuse aluminum and silicon into the superalloy rich in rhenium. Method. 26. A method for aluminizing a rhenium-containing single crystal superalloy as described in the specification and illustrated in FIGS. 5 and 6 of the drawings. 27. A method for aluminizing a rhenium-containing single crystal superalloy as described herein. 28. A superalloy product having an aluminide coating formed by the method according to any one of claims 1 to 27.